PROJECT SUMMARY The prevalence of disruptive behavior problems among deaf or hard of hearing (DHH) children is double that of normal hearing children, but this underserved population rarely receives behavioral interventions. Behavioral problems in DHH children often are attributed to delays in language development, yet even when language outcomes improve in response to early intervention, behavioral problems frequently persist. Although parenting behaviors have been largely overlooked in the literature investigating the etiology and maintenance of disrup- tive behavior problems in young DHH children, their effects on child behavior are well-established in the normal hearing population. Behavioral parent training (BPT) programs have consistently demonstrated efficacy and effectiveness in reducing disruptive behavior problems, comorbidities, parental stress and depression, and long-term costly consequences in children with normal hearing, especially when delivered in early childhood. The hearing healthcare setting is ideal as a delivery venue for behavioral services, because of consistent con- tacts from infancy through adolescence; parents? trust and familiarity with the setting and providers; and lack of stigma. This type 1 hybrid effectiveness-implementation trial will be conducted in 10 state-funded hearing healthcare clinics, testing an evidence-based BPT adapted to meet the needs of parents of underserved DHH children. The specific aims are: (1) To systematically adapt an evidence-based BPT by incorporating the pref- erences and perspectives of the target population and key stakeholders; (2) using a cluster-randomized trial design, to test the effects of the adapted BPT on parent behaviors, child behaviors, adherence to wearing hearing rehabilitation devices, and language development outcomes; and (3) based on the Consolidated Framework of Implementation Research, to identify factors within the domains of the inner setting, outer set- ting, intervention characteristics, process, and provider characteristics influencing implementation of the inter- vention in each clinic, as well as implementation outcomes (i.e., acceptability, adoption, recruitment/retention, fidelity, and costs). The ADAPT-ITT framework will guide the systematic adaptation process. Examples of pos- sible adaptations include modifications to content (e.g., incorporation of scenarios relevant to DHH children in materials and activities, inclusion of facilitative language techniques in skills training) and context (e.g., delivery in hearing healthcare settings, incorporation of language and hearing data in behavioral assessments). If the adapted BPT is effective, behavioral problems among DHH children could be successfully addressed in hear- ing healthcare. The use of a type I hybrid design will allow us to simultaneously test effectiveness and gather information on multilevel factors influencing the quality of implementation. Results of this study will inform hear- ing healthcare systems regarding resources and strategies needed to deliver this intervention in new settings to a new population. This project could inform a transformation of care in hearing healthcare settings to scale up the integration of much-needed behavioral services into their already-interdisciplinary clinics.